diff options
Diffstat (limited to 'src/win32/w32_crtdbg_stacktrace.c')
| -rw-r--r-- | src/win32/w32_crtdbg_stacktrace.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/src/win32/w32_crtdbg_stacktrace.c b/src/win32/w32_crtdbg_stacktrace.c new file mode 100644 index 000000000..a778f4164 --- /dev/null +++ b/src/win32/w32_crtdbg_stacktrace.c @@ -0,0 +1,343 @@ +/* + * Copyright (C) the libgit2 contributors. All rights reserved. + * + * This file is part of libgit2, distributed under the GNU GPL v2 with + * a Linking Exception. For full terms see the included COPYING file. + */ + +#if defined(GIT_MSVC_CRTDBG) +#include "w32_stack.h" +#include "w32_crtdbg_stacktrace.h" + +#define CRTDBG_STACKTRACE__UID_LEN (15) + +/** + * The stacktrace of an allocation can be distilled + * to a unique id based upon the stackframe pointers + * and ignoring any size arguments. We will use these + * UIDs as the (char const*) __FILE__ argument we + * give to the CRT malloc routines. + */ +typedef struct { + char uid[CRTDBG_STACKTRACE__UID_LEN + 1]; +} git_win32__crtdbg_stacktrace__uid; + +/** + * All mallocs with the same stacktrace will be de-duped + * and aggregated into this row. + */ +typedef struct { + git_win32__crtdbg_stacktrace__uid uid; /* must be first */ + git_win32__stack__raw_data raw_data; + unsigned int count_allocs; /* times this alloc signature seen since init */ + unsigned int count_allocs_at_last_checkpoint; /* times since last mark */ + unsigned int transient_count_leaks; /* sum of leaks */ +} git_win32__crtdbg_stacktrace__row; + +static CRITICAL_SECTION g_crtdbg_stacktrace_cs; + +/** + * CRTDBG memory leak tracking takes a "char const * const file_name" + * and stores the pointer in the heap data (instead of allocing a copy + * for itself). Normally, this is not a problem, since we usually pass + * in __FILE__. But I'm going to lie to it and pass in the address of + * the UID in place of the file_name. Also, I do not want to alloc the + * stacktrace data (because we are called from inside our alloc routines). + * Therefore, I'm creating a very large static pool array to store row + * data. This also eliminates the temptation to realloc it (and move the + * UID pointers). + * + * And to efficiently look for duplicates we need an index on the rows + * so we can bsearch it. Again, without mallocing. + * + * If we observe more than MY_ROW_LIMIT unique malloc signatures, we + * fall through and use the traditional __FILE__ processing and don't + * try to de-dup them. If your testing hits this limit, just increase + * it and try again. + */ + +#define MY_ROW_LIMIT (1024 * 1024) +static git_win32__crtdbg_stacktrace__row g_cs_rows[MY_ROW_LIMIT]; +static git_win32__crtdbg_stacktrace__row *g_cs_index[MY_ROW_LIMIT]; + +static unsigned int g_cs_end = MY_ROW_LIMIT; +static unsigned int g_cs_ins = 0; /* insertion point == unique allocs seen */ +static unsigned int g_count_total_allocs = 0; /* number of allocs seen */ +static unsigned int g_transient_count_total_leaks = 0; /* number of total leaks */ +static unsigned int g_transient_count_dedup_leaks = 0; /* number of unique leaks */ +static bool g_limit_reached = false; /* had allocs after we filled row table */ + +static unsigned int g_checkpoint_id = 0; /* to better label leak checkpoints */ +static bool g_transient_leaks_since_mark = false; /* payload for hook */ + +/** + * Compare function for bsearch on g_cs_index table. + */ +static int row_cmp(const void *v1, const void *v2) +{ + git_win32__stack__raw_data *d1 = (git_win32__stack__raw_data*)v1; + git_win32__crtdbg_stacktrace__row *r2 = (git_win32__crtdbg_stacktrace__row *)v2; + + return (git_win32__stack_compare(d1, &r2->raw_data)); +} + +/** + * Unique insert the new data into the row and index tables. + * We have to sort by the stackframe data itself, not the uid. + */ +static git_win32__crtdbg_stacktrace__row * insert_unique( + const git_win32__stack__raw_data *pdata) +{ + size_t pos; + if (git__bsearch(g_cs_index, g_cs_ins, pdata, row_cmp, &pos) < 0) { + /* Append new unique item to row table. */ + memcpy(&g_cs_rows[g_cs_ins].raw_data, pdata, sizeof(*pdata)); + sprintf(g_cs_rows[g_cs_ins].uid.uid, "##%08lx", g_cs_ins); + + /* Insert pointer to it into the proper place in the index table. */ + if (pos < g_cs_ins) + memmove(&g_cs_index[pos+1], &g_cs_index[pos], (g_cs_ins - pos)*sizeof(g_cs_index[0])); + g_cs_index[pos] = &g_cs_rows[g_cs_ins]; + + g_cs_ins++; + } + + g_cs_index[pos]->count_allocs++; + + return g_cs_index[pos]; +} + +/** + * Hook function to receive leak data from the CRT. (This includes + * both "<file_name>:(<line_number>)" data, but also each of the + * various headers and fields. + * + * Scan this for the special "##<pos>" UID forms that we substituted + * for the "<file_name>". Map <pos> back to the row data and + * increment its leak count. + * + * See https://msdn.microsoft.com/en-us/library/74kabxyx.aspx + * + * We suppress the actual crtdbg output. + */ +static int __cdecl report_hook(int nRptType, char *szMsg, int *retVal) +{ + static int hook_result = TRUE; /* FALSE to get stock dump; TRUE to suppress. */ + unsigned int pos; + + *retVal = 0; /* do not invoke debugger */ + + if ((szMsg[0] != '#') || (szMsg[1] != '#')) + return hook_result; + + if (sscanf(&szMsg[2], "%08lx", &pos) < 1) + return hook_result; + if (pos >= g_cs_ins) + return hook_result; + + if (g_transient_leaks_since_mark) { + if (g_cs_rows[pos].count_allocs == g_cs_rows[pos].count_allocs_at_last_checkpoint) + return hook_result; + } + + g_cs_rows[pos].transient_count_leaks++; + + if (g_cs_rows[pos].transient_count_leaks == 1) + g_transient_count_dedup_leaks++; + + g_transient_count_total_leaks++; + + return hook_result; +} + +/** + * Write leak data to all of the various places we need. + * We force the caller to sprintf() the message first + * because we want to avoid fprintf() because it allocs. + */ +static void my_output(const char *buf) +{ + fwrite(buf, strlen(buf), 1, stderr); + OutputDebugString(buf); +} + +/** + * For each row with leaks, dump a stacktrace for it. + */ +static void dump_summary(const char *label) +{ + unsigned int k; + char buf[10 * 1024]; + + if (g_transient_count_total_leaks == 0) + return; + + fflush(stdout); + fflush(stderr); + my_output("\n"); + + if (g_limit_reached) { + sprintf(buf, + "LEAK SUMMARY: de-dup row table[%d] filled. Increase MY_ROW_LIMIT.\n", + MY_ROW_LIMIT); + my_output(buf); + } + + if (!label) + label = ""; + + if (g_transient_leaks_since_mark) { + sprintf(buf, "LEAK CHECKPOINT %d: leaks %d unique %d: %s\n", + g_checkpoint_id, g_transient_count_total_leaks, g_transient_count_dedup_leaks, label); + my_output(buf); + } else { + sprintf(buf, "LEAK SUMMARY: TOTAL leaks %d de-duped %d: %s\n", + g_transient_count_total_leaks, g_transient_count_dedup_leaks, label); + my_output(buf); + } + my_output("\n"); + + for (k = 0; k < g_cs_ins; k++) { + if (g_cs_rows[k].transient_count_leaks > 0) { + sprintf(buf, "LEAK: %s leaked %d of %d times:\n", + g_cs_rows[k].uid.uid, + g_cs_rows[k].transient_count_leaks, + g_cs_rows[k].count_allocs); + my_output(buf); + + if (git_win32__stack_format( + buf, sizeof(buf), &g_cs_rows[k].raw_data, + NULL, NULL) >= 0) { + my_output(buf); + } + + my_output("\n"); + } + } + + fflush(stderr); +} + +void git_win32__crtdbg_stacktrace_init(void) +{ + InitializeCriticalSection(&g_crtdbg_stacktrace_cs); + + EnterCriticalSection(&g_crtdbg_stacktrace_cs); + + _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF); + + _CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE); + _CrtSetReportMode(_CRT_ERROR, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE); + _CrtSetReportMode(_CRT_WARN, _CRTDBG_MODE_DEBUG | _CRTDBG_MODE_FILE); + + _CrtSetReportFile(_CRT_ASSERT, _CRTDBG_FILE_STDERR); + _CrtSetReportFile(_CRT_ERROR, _CRTDBG_FILE_STDERR); + _CrtSetReportFile(_CRT_WARN, _CRTDBG_FILE_STDERR); + + LeaveCriticalSection(&g_crtdbg_stacktrace_cs); +} + +int git_win32__crtdbg_stacktrace__dump( + git_win32__crtdbg_stacktrace_options opt, + const char *label) +{ + _CRT_REPORT_HOOK old; + unsigned int k; + int r = 0; + +#define IS_BIT_SET(o,b) (((o) & (b)) != 0) + + bool b_set_mark = IS_BIT_SET(opt, GIT_WIN32__CRTDBG_STACKTRACE__SET_MARK); + bool b_leaks_since_mark = IS_BIT_SET(opt, GIT_WIN32__CRTDBG_STACKTRACE__LEAKS_SINCE_MARK); + bool b_leaks_total = IS_BIT_SET(opt, GIT_WIN32__CRTDBG_STACKTRACE__LEAKS_TOTAL); + bool b_quiet = IS_BIT_SET(opt, GIT_WIN32__CRTDBG_STACKTRACE__QUIET); + + if (b_leaks_since_mark && b_leaks_total) { + giterr_set(GITERR_INVALID, "Cannot combine LEAKS_SINCE_MARK and LEAKS_TOTAL."); + return GIT_ERROR; + } + if (!b_set_mark && !b_leaks_since_mark && !b_leaks_total) { + giterr_set(GITERR_INVALID, "Nothing to do."); + return GIT_ERROR; + } + + EnterCriticalSection(&g_crtdbg_stacktrace_cs); + + if (b_leaks_since_mark || b_leaks_total) { + /* All variables with "transient" in the name are per-dump counters + * and reset before each dump. This lets us handle checkpoints. + */ + g_transient_count_total_leaks = 0; + g_transient_count_dedup_leaks = 0; + for (k = 0; k < g_cs_ins; k++) { + g_cs_rows[k].transient_count_leaks = 0; + } + } + + g_transient_leaks_since_mark = b_leaks_since_mark; + + old = _CrtSetReportHook(report_hook); + _CrtDumpMemoryLeaks(); + _CrtSetReportHook(old); + + if (b_leaks_since_mark || b_leaks_total) { + r = g_transient_count_dedup_leaks; + + if (!b_quiet) + dump_summary(label); + } + + if (b_set_mark) { + for (k = 0; k < g_cs_ins; k++) { + g_cs_rows[k].count_allocs_at_last_checkpoint = g_cs_rows[k].count_allocs; + } + + g_checkpoint_id++; + } + + LeaveCriticalSection(&g_crtdbg_stacktrace_cs); + + return r; +} + +void git_win32__crtdbg_stacktrace_cleanup(void) +{ + /* At shutdown/cleanup, dump cummulative leak info + * with everything since startup. This might generate + * extra noise if the caller has been doing checkpoint + * dumps, but it might also eliminate some false + * positives for resources previously reported during + * checkpoints. + */ + git_win32__crtdbg_stacktrace__dump( + GIT_WIN32__CRTDBG_STACKTRACE__LEAKS_TOTAL, + "CLEANUP"); + + DeleteCriticalSection(&g_crtdbg_stacktrace_cs); +} + +const char *git_win32__crtdbg_stacktrace(int skip, const char *file) +{ + git_win32__stack__raw_data new_data; + git_win32__crtdbg_stacktrace__row *row; + const char * result = file; + + if (git_win32__stack_capture(&new_data, skip+1) < 0) + return result; + + EnterCriticalSection(&g_crtdbg_stacktrace_cs); + + if (g_cs_ins < g_cs_end) { + row = insert_unique(&new_data); + result = row->uid.uid; + } else { + g_limit_reached = true; + } + + g_count_total_allocs++; + + LeaveCriticalSection(&g_crtdbg_stacktrace_cs); + + return result; +} +#endif |